This invention concerns a combine harvester in which an axial flow rotary separator receives threshed material from a threshing cylinder and concave extending transversely with respect to the separator and, more particularly, to means for conveying the threshed material from the threshing cylinder and feeding it efficiently to an inlet of the separator. The invention may also be applied to feeding of axial flow rotary separators which include an axial threshing portion.
Combine harvesters in which an axial flow rotary separator consisting of one or perhaps two side-by-side separator units receive threshed material from a cylinder and concave upstream of the separator are well known. See, for example U.S. patent application Ser. No. 646,346, now U.S. Pat. No. 4,611,605 Hall et al, also assigned to the assignee of the present invention. This configuration is attractive. It combines the predictable and well understood virtually universal crop performance of the conventional threshing cylinder and concave (circumferentially fed) and the space-saving potential of the axial flow rotary separator. However, in the most convenient layout, the separator must be fed in a generally axial direction and, as is well known, efficient and trouble-free feeding in this configuration is difficult to achieve. The problem is largely that of bringing a linear stream of crop material into engagement with a rapidly rotating rotor and having it carried smoothly into a separator casing as an annular mat with a minimum of rejection and recirculation of material.
While the arrangement disclosed by Hall functions well in a wide variety of conditions, it has some limitations, manifested in more difficult crop conditions when feeding tends to be pulsating and erratic. In twin rotor machines, material in the feed section may be recirculated around a rotor and transferred from one rotor to the other, with delays of downstream axial indexing of the material and of its entrance into the contained environment of the separator casing proper.